Method of drying work without droplet formation



PUMP

- GEAR J. C. WILLIAMSON Filed Oct. 22, 1965 METHOD OF DRYING WORK WITHOUT DROPLET FORMATION FIG Ill/Ill Jan. 30, 1968 Fl 6 2 INVENTOR.

JAMES C WILLIAMSON ATTORNEY ////3 F I G 4 M l/ w \N H m v 2 3 4 Q 3 W v w V \\m B //7///// United States Patent 3,365,807 METHOD OF DRYING WORK WITHOUT DROPLET FORMATION James C. Williamson, 522 S. 6th St., Mentebello, Calif. 90640 Filed Oct. 22, 1965, Ser. No. 501,475 7 Claims. (Cl. 34-9) ABSTRACT OF THE DISCLOSURE This invention relates to a method for removing water or a treating solution from the surface of work without permitting droplets of liquid to adhere to the work. These droplets form hard to remove spots on the surface of the work when they evaporate. This method is based on the prevent the droplets from adhering to the surface of the work. Therefore, in order to dry work without permitting droplets to adhere to the surface of the work it is necessary to take a sample of the work and raise it through the drying solution at a gradually decreasing, but always very constant speed, until a critical speed is discovered below which the droplets no longer adhere to the work.

Thereafter, the remainder of the work is raised up through the drying solution at a slow, very constant speed below the determined critical speed.

This invention relates to a method and apparatus for removing water or an aqueous treating solution from the surface of treated work.

In many processes, such as plating, anodizing, passivating, etc. wherein the surface of work is treated, it is necessary to remove the treating solution from the work when the process is completed. This is often done by washing the work with water or some suitable aqueous solution. After that the work must be dried.

Some drying processes involve the use of heat with suitably positioned fans for blowing hot air over the work. However these procedures are objectionable, both because of the expense involved and because as the water evaporates it gathers into droplets which when they dry leave spots or stains on the work. Such spots or stains can only be removed by a tedious and expensive resort to hand wiping, and in some cases, depending on the configuration of the work even these laborious techniques are not sufficient Another method that is widely used for drying water wet articles is tumbling them in barrels of sawdust. However this procedure is slow and inconvenient for treating large articles. In addition it causes problems in separating the treated articles from the sawdust. Finally because a film of fine dust adheres to the work, resort must again be made to hand wiping.

Still another method used for drying water wet articles is to dip them into a tank containing an emulsification of water with fish oil or water with other suitable organic water insoluable fluid containing an emulsifying agent. This method works because the water or aqueous treating solution on the surface of the work is replaced by the emulsion so that when the work is removed from the tank, the surface of the work is coated by the emulsified mixture of the water with the organic water insoluable fluid. However when dried this way, tiny droplets of water or "ice the aqueous treating solution are found to adhere to the work and cause spots. As described above when these drops evaporate they leave marks which mar the finish of the work, so again resort must be made to hand rubbiug to eliminate these marks.

Consequently none of the processes for drying work heretofore known were particularly satisfactory because they all required hand rubbing when the appearance of the work was important and they did not prevent tiny droplets of water or the aqueous treating solution from adhering to the work and spotting it.

What is needed therefore and comprises an important object of this invention is to provide an apparatus and method for drying work without requiring hand rubbing and which does not cause spots and stains to appear on the surface of the work.

This and other objects of this invention will become more apparent when better understood in the light of the accompanying drawing and specification wherein:

FIG. 1 is a schematic diagram of the drying device shown utilizing a hydraulic unit for raisng and lowering the work.

FIG. 2 is a circuit diagram showing the control of the solenoid valves used in the hydraulic units shown in FIG. 1.

FIG. 3 is a control circuit for the motor operating the gear pump.

FIG. 4 is a partial elevational view showin a dwell mechanism for the drying device.

Referring now to FIG. 1 of the drawing, a schematic diagram of the drying device indicated generally by the reference numeral comprises a tank 12 filled with an emulsification of water with fish oil or other suitable water insoluble fluid. The tank 12 is provided with an overflow channel 13 for reasons to be described below. In addition the tank is provided with an inlet 15 at the bottom thereof to permit the emulsified fluid to enter the tank without causing surface turbulence. The tank 12 is formed or lined with a suitably chemically inert material for reasons to become apparent below.

A hydraulic unit is suspended over tank 12. The hydraulic unit comprises a support rod 16 attached at one end to a piston 18. The piston 18 is slidably movable inside hydraulic cylinder 20, as shown in the drawing. The support rod 16 is designed to be raised or lowered toward tank 12 in accordance with the movement of piston 18 inside the cylinder 20.

The lower end of support rod 16, in this particular embodiment, terminates in a sleeve 22 in which a coil spring 24 is mounted. The upper end 26 of a work support rod 28 is slidably mounted inside sleeve 22. The coil spring 24 biases the work support'rod 28 outwardly, but the work support rod 28 can telescope upwardly inside sleeve 22 when force is directed upwardly against the lower end 30 of the work support rod 28 to provide time for the Work to dwell in the emulsion. A transverse support member or disk 32 carrying work supporting hooks 34- is rigidly attached to the work support rod 28, as shown in FIG. 1. The upper end 26 of the work support rod 28 is enlarged to provide a bearing surface for the coil spring 22. The lower end of sleeve 22 is bent inwardly as shown in FIG. 4 to retain the work support rod 28 inside the sleeve. It is of course understood that where dwell is not required, the support rod 16 would be able to move into tank 12 and the transverse support member or disk 32 would be attached directly to support rod v16.

The hydraulic cylinder 20 is part of the hydraulic unit for raising and lowering the work inside tank 12. This hydraulic unit comprises a hydraulic oil supply tank 36 filled with a suitable oil 38. A tank outlet pipe 40 leads from tank 36 to a gear pump 42. As shown in FIG. 3,

gear pump 42 is powered by a suitable electric motor 44.

The gear pump 42 draws oil up through the tank outlet pipe 40 and forces it through the gear pump outlet pipe 46. This oil is then forced through a conventional variable flow valve 48 which has an oil bypass return pipe 50 leading back to the oil supply tank 36, and outlet pipe 52.

With this arrangement, the rate of flow of oil through V the part of the hydraulic units connected to the hydraulic cylinder can be regulated by a suitable adjustment of the variable flow valve 48 in a manner well known in the art. In this way the rate of speed of piston 18 inside cylinder 20 can be precisely controlled for reasons to be described below. The outlet pipe 52 divides into two branches 54 and 56. Solenoid valve SV2 is connected in branch pipe 54 and solenoid valve SV3 is connected in branch pipe 56. As will be explained below, solenoid valve SV2 is open when de-energized and solenoid valve SV3 is closed when de-energized. Similarly colenoid valve SVl is closed when de-energized. All of the solenoid valves shown in FIG. 1 are in their de-energized position. When these solenoid valves become energized, solenoid valve SV1 rotates to an open position, solenoid valve SV2 rotates to a closed position, solenoid valve SV3 rotates to an open position and solenoid valve 8V4 rotates to-a closed position. When these solenoid valves are once again de-energized they all automatically rotate to their deenergized position in a manner well known in the art.

As stated above, solenoid valve SV2 is open and SV3 is closed so oil flows from branch pipe 54 through solenoid valve SV2 and on into branch pipe 58. Branch pipe 58 itself divides into the cylinder pipe 60 and branch pipe 62. Solenoid valve SVl is in branch pipe 62 and as shown in FIG. 1, is in its de-energized closed position. Hence oil from gear pump 42 flows through the cylinder inlet pipe 60 and on into hydraulic cylinder 20 forcing piston 18 inside the cylinder downwardly in a manner well known in the art.

The hydraulic cylinder 20 is provided with a cylinder pipe 64. The cylinder pipe 64 joins branch 56 and the oil return pipe '66. Solenoid valve SV4, in its de-energized position is in the oil return pipe 66, as shown in FIG. 1.

With this arrangement the gear pump 42 pumps oil through pipes 52, 58, and 60 and on into cylinder 20. The oil in cylinder 20 returns to tank 64 through lines 64 and 66 while the piston is moving downwardly in cylinder 20.

When the solenoid valves are all energized, oil from pump 42 finds branch pipe 54 closed by solenoid valve SV2, but solenoid valve SV3 is open so oil can flow into branch 56. Solenoid valve SV4- is closed when energized so oil cannot move through return pipe 66. Consequently the oil flows through cylinder pipe 64 into cylinder 20 causing piston 18 to rise in the cylinder. The oil in cylinder 20 leaves the. cylinder through cylinder pipe 60 and since solenoid valve 8V1 is open, oil can flow through pipe 62 and back to tank 36 through the oil return pipe 68. As stated above, the speed of movement of piston 18 in cylinder 20, regardless of its direction is controlled by a suitable adjustment of the variable control valve 48. In this way, work can be suspended on books 34 and lowered into or raised out of tank 12 containing the emulsified solution 14.

As stated above, process for drying or removing water or the aqueous treating solution from the surface of the work have heretofore involved dipping the work into a tank containing a suitable emulsification of water and fish oil or the like, but such processes were not satisfactory because tiny droplets of the water or aqueous treating solution adhered to the work when the work was removed from the tank. When these droplets dried they left stains which marred the finish of the work. When the appearance of the finish was important, the removal of these stains required hand rubbing which was expensive and time consuming.

However applicant discovered that these droplets would not adhere to the work if the work was raised from the tank at a slow constant speed. In particular applicant discovered that while the work is being raised through the emulsion turbulence must be avoided and the speed of removal of the Work from the tank was critical and depended on the complexity of the surface of the work. In general applicant discovered that the simpler the external shape of the work the faster the work could be removed without causing droplets to adhere. However all the permissible speeds were rather low, usually below 6 feet per minute and in some cases below a /2 foot per minute. Applicant discovered that for work of any given configuration there was a critical removal speed such that if the removal speed was greater than their critical speed these tiny droplets would adhere. Applicant also discovered that in addition to removing the work at the proper speed the removal speed had to be constant. These two requirements imposed limitations on the design of the equipment for raising and lowering the work.

As described above the use of a hydraulic unit in applicants dryer satsifies the requirement for a mechanism that can raise and lower work at a constant speed and the variable control valve 48 in the hydraulic unit provides the speed control required.

Economic considerations as well as the critical requirements for a constant, controlled speed require the drying process to be as automatic as possible. Consequently electrical control circuits for the hydraulic unit are required.

The electric pump 42 driven by motor 44 is provided with a control circuit 70, see FIG. 3. This control circuit comprises a double contact relay 72 including a coil 74 and contacts 76 and 78. The control circuit further includes a two contact push button start switch and a normally closed disconnect switch SW3 connected as shown in FIG. 3.

In operation, when the push button start switch 80 is pressed, contacts 116 and 118 also cose and the relay 70 is energized causing contacts 76 and 78 to close. This starts motor 44 operating and the push button start switch 80'is by-passed through switch SW3. Consequently the relay remains energized and contacts 76 and 78 remain closed even after the push button start switch 80 opens. With this arrangement, once push button 80 is pressed motor 44 operates independently of switch 80 so long as switch SW3 is closed.

The hydraulic unit is provided with a control circuit 84. This control circuit is provided with a source of electric power 86. Control circuit 84 also includes a double contact relay 88 comprising a coil 90 and contacts 92 and 94. A switch SW1 is connected between the power source 86 and coil 90. When this switch is closed, the relay is actuated closing contacts 92 and 94 and there by energizing all the solenoid valves SVl, SV2, SV3, and

SV4. Further once switch SW1 is closed, it is bypassed through relay contact 92 so the solenoid valves all remain energized independently of switch SW1. The solenoid valves remain energized until normally closed switch SW2 connected as shown in FIG. 2 is opened. When this happens relay coil 90 and all the solenoid valves become de-energized and contacts 92 and 94 open.

Support rod 16 is provided with an attached radially extending arm 96. This arm is designed to engage resilient support 97 which carries one contact 98 of switch SW1. The other contact is mounted on any suitable support in a fixed position with respect to a support. As the support rod 16 descends toward tank 12, arm 96 engages support 97 and bends it until contacts 98 and 100 engage and close switch SW1 at the limit of downward movement of rod 16.

This as explained above energizes all the solenoid valves and causes the piston 18 to reverse direction. This causes work support 28 to move upward lifting work attached to hooks 34 out of the tank. As stated above the solenoid valves remain energized even when contacts 98 and 100 separate opening switch SW1.

A radially extending push arm 102 is also connected to support rod 16 as shown. This push arm is in the path of one end of a resilient support 104. One end of the resilient support is connected to a fixed support.

The resilient support 104 carries contacts 106 and 108. An adjacent support 110 carries contacts 112 and 114. Contacts 108 and 114 together form switch SW3 and contacts 106 and 112 form switch SW2.

As support rod 104 moves up out of tank 12 arm 102 engages the end of resilient support 104. Normally contacts 106 and 112, and 108 and 114 engage each other so switches SW2 and SW3 are normally closed. But when push arm 102 engages the resilient support 104, contacts 106 and 112 and contacts 108 and 114 are forced out of engagement with each other so that the switches SW2 and SW3 open.

When this happens as explained above motor 44 driving gear pump 42 stops and all the solenoid valves are de-energized which sets the piston 18 for movement in a reverse direction when the push button start switch 80 is again pressed.

The push button start switch 80 is a two contact switch and includes contacts 116 and 118 which bypass switch SW3, see FIG. 3. When the push button start switch 80 is pressed contacts 116 and 118 close. This arrangement is important because when the arm 102 on support rod 16 causes switches SW2 and SW3 to open, the motor 44 could not be started with switch SW3 open unless the push button switch 80 also caused switch SW3 to be bypassed. The push button switch 80 must be pressed long enough to permit support rod 16 and arm 102 to move downwardly away from the resilient support 104 so that switches SW2 and SW3 can close automatically.

In some circustances it may be desirable to cause the work to dwell in the drying solution in tank 12 for a period of time. This can be accomplished in a variety of ways. In the example shown in FIGS. 1 and 4 dwell, if necessary, is provided by having a work support rod 28 telescope up inside of sleeve 22. in operation, when work is loaded on hooks 34 and the support rod 16 is lowered into tank 12, as the base of work support rod 23 touches the bottom of the tank, further downward movement is stopped. However support rod 16 and sleeve 22 can continue to move downward over rod 23 until arm 96 causes contacts 98 and 100 to engage thereby closing switch SW1 and reversing the direction of movement of piston 18 and support rod 16. It is evident and it is contemplated that arm 96 can be adjustably mounted on support rod 16 for movement upwards or downwards by any suitable means (not shown) to thereby provide a convenient way to vary the dwell time of the work in the tank. Although the embodiment shown in the drawing is used with the dwell mechanism described above, it will be understood that the use of the dwell mechanism is not essential to the practice of this invention, and has been included in the mechanism shown in the drawing for work having certain shapes which require a more extended emersion time for drying.

In operation, a sample of the work to be dried is usually first rinsed with water and is then suspended on a hook 34. Then the operator presses the start button 80 causing the work to descend into the solution 14 in tank 12. When the support arm 16 descends far enough arm 96 will cause switch SW1 to close as described above. This energizes all the solenoid valves causing the support rod 16 and work support rod 28 to lift the work out of the solution 14. When the support rod 16 rises high enough arm 102 causes switch SW2 and SW3 to open. This stops the motor driving the gear pump 42 and de-energizes all the solenoid valves so they rotate back to their de-energized position shown in FIG. 1, thereby setting the support rod 16 for downward movement again when the start push button 80 is pressed again. The work is then inspected and if it appears that spots of water have adhered to the work, another sample is attached to hook 34 and valve 48 is adjusted for a slower piston speed, and the work is then run through the drying cycle again. This procedure is continued until the critical speed is determined for the particular work, below which the droplets of water or treating solution no longer adhere to the work. Then with the speed of the dryer properly adjusted the work is fed into the dryer for production purposes. As the drying operation continues a film of oil and dirt, etc. tends to float on the surface of the emulsion. This must be eliminated and if a continuous supply of emulsion is slowly and gently fed into tank 12 through inlet 15, this film will overflow into the overflow channel 13 and the resulting work will appear noticeably brighter and cleaner.

While the invention has been described in connection with a specific embodiment and application, other modifications will become readily apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

1. An apparatus for drying work rinsed in water or treated in an aqueous solution comprising a tank, said tank filled with an emulsion of water and fish oil, said tank having an inlet at the bottom and an overflow channel at the top, means for gently adding emulsion to the tank through said inlet until the level of the emulsion is at the same level as the overflow channel so that any film on the top surface of the emulsion overflows into the overflow channel, a hydraulic unit associated with the tank for lowering work into the tank and lifting it out of the tank at a constant predetermined speed, said hydraulic unit having means for varying the speed the work is lifted out of the tank, automatic dwell means for automatically causing the work to remain in the tank for a predetermined period, means for varying the dwell period of time the work remains in the tank, and a control system for the hydraulic unit for causing the hydraulic unit to run through an automatic cycle wherein the hydraulic system lowers work into the tank, lets the work dwell there for a predetermined period, lifts the work out of the tank at a constant predetermined speed and then stops to complete the cycle.

2. A method for drying work rinsed in water or treated in an aqueous treating solution comprising the steps of dipping successive samples of the work in a tank filled with an emulsion of water and a water insoluble fluid, then lifting the work out of the emulsion at a constant speed, then decreasing the speed with each successive sample until a critical speed is determined below which droplets of water or treating solution no longer adhere to the surface of the work, then dipping the remainder of the work in the emulsion and lifting it out of the liquid at a constant speed and at a speed below the determined critical speed, gently adding the emulsion to the tank while removing oily film and dirt accumulating from the work at the surface of the emulsion.

3. The method described in claim 2 wherein said water insoluble fluid is fish oil.

4. A method for drying work rinsed in water or treated in an aqueous treating solution comprising the steps of dipping a sample of the work in a tank filled with a liquid, then lifting the work out of the liquid at a constant speed, then repeating this step but decreasing the speed until a critical speed is found below which droplets of the liquid no longer adhere to the surface of the work, then dipping the remainder of the work in the liquid and lifting it out of the liquid at a constant speed and at a speed below the determined critical speed, gently adding liquid to the tank while removing oily film and dirt accumulating from the work on the surface of the liquid.

5. A method for drying work rinsed in water or treated in an aqueosu treating solution comprising the steps of dipping a sample of the work in a liquid comprising an emulsion of water and a water displacing liquid, permitting the work to dwell in the liquid for a predetermined period,

lifting the work out of the liquid at a very constant speed, then repeating this step but decreasing the speed until a critical speed is found below which droplets of the liquid no longer adhere to the surface of the Work, then dipping the remainder of the work in the liquid and lifting it out of the liquid at a constant speed and at a speed below the predetermined critical speed and adding liquid at a point below the surface of the liquid at the same rate oily film and dirt accumulating from the work is removed from the surface of the liquid.

6. An apparatus for drying work rinsed in water or treated in an aqueous solution comprising a tank, said tank filled with a liquid, said tank having an inlet at the bottom and an overflow channel at the top, means for gently adding liquid to the tank through said inlet until the level of the liquid is at the same level and the overflow channel so that any film on the top surface of the liquid overflows into the overflow channels, a mechanism associated with the tank for lowering work into the tank and lifting it out of the tank at a constant predetermined speed, said mechanism having means for varying the speed the work is lifted out of the tank, and a control system for the mechanism for causing the mechanism to run through an automatic cycle wherein the mechanism lowers work into the tank, and lifts the work out of the tank at a constant predetermined speed and then stops to complete the cycle.

7. In the apparatus for drying work rinsed in water or treated in an aqueous solution comprising a tank. Said tank filled with a liquid, said tank having an inlet at the bottom and an overflow channel at the top, means for gently adding liquid to the tank through such inlet until the level of the liquid is at the same level and the overflow channel so that any film On the top surface of the liquid overflows into the overflow channel, a mechanism associated with the tank for lowering the work into the tank and lifting it out of tank at a constant predetermined speed, said mechanism having means for varying the speed work is lifted out of the tank, automatic dwell means for automatically causing the work to remain in the tank for a predetermined period, means for varying the dwell period of time work remains in the tank and a control system for the mechanism for causing the mechanism to run through an automatic cycle wherein the hydraulic system lowers work into the tank, lets the work dwell there for a predetermined period, lifts the work out of the tank at a constant predetermined speed and then stops to complete the cycle.

References Cited UNITED STATES PATENTS 1,665,927 4/1928 Kendall 134141 2,649,764 8/1953 Eftihios 134-455 X 2,724,392 11/1955 Cooper 134-141 X 2,781,590 2/1957 Heckman et al 349 X 3,003,247 10/1961 Sherliker 34-9 CHARLES I. MYHRE, Primary Examiner.

FREDERICK L. MATTESON, JR., JOHN I. CAMBY,

Examiners. 

